Apparatus and method for three-dimensional printing

ABSTRACT

A three-dimensional printing apparatus includes a liquid tank and a motor. The liquid tank includes a film and a plate. The film has a working area, and the plate supports the film and has at least one fluid tunnel extending from a first surface of the plate contacting the film to a second surface of the plate. The motor is disposed on the liquid tank, providing dragging-down traction to incline the liquid tank. The embodiments of the present invention facilitate the separation of workpieces from the film. Another three-dimensional printing apparatus and a three-dimensional printing method are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part application claimingbenefit from a parent U.S. patent application bearing a Ser. No.15/014,811 and filed Feb. 3, 2016, contents of which are incorporatedherein for reference.

FIELD OF THE INVENTION

The present invention relates to a printing apparatus, and moreparticularly to an apparatus and method for three-dimensional printing.

BACKGROUND OF THE INVENTION

In conventional light curing three-dimensional printing devices, a filmand a plate for supporting the film are disposed on the bottom of a tankfor accommodating photosensitive resins. In printing of a workpiece, thephotosensitive resins would be cured to form a layer of the workpieceand adhere to the film. To initiate printing of the following layer,applying a force to lift up the workpiece is required to separate theworkpiece from the film and allow uncured photosensitive resins to fillbetween the workpiece and the film. However, in conventionalthree-dimensional printing devices, the space between the film and theplate becomes airtight during printing of a workpiece andlow-pressure/vacuum builds up therewithin during releasing of theresulting workpiece, therefore causing difficulties in separating theworkpiece from the film.

While increasing the uplift force may be helpful in separating theworkpiece from the film, application of strong uplift forces often leadsto damage of the workpiece and deformation of the film.

BRIEF SUMMARY OF THE INVENTION

An embodiment of the present invention provides a three-dimensionalprinting apparatus for facilitating the separation of workpieces fromthe film.

A three-dimensional printing apparatus according to an embodiment of thepresent invention includes a liquid tank, a light source device, and aplatform. The liquid tank is configured for accommodating aphotosensitive liquid. The liquid tank includes a film and a plate. Thefilm has a working area; the plate supports the film and has a firstarea corresponding to the working area and a second area adjacent to thefirst area; and the plate has at least one fluid tunnel extending from asurface of the plate contacting the film to another surface of theplate. The light source device is disposed below the liquid tank forproviding an curing light beam passing through the plate and irradiatingthe working area. The platform and the plate are disposed on twoopposite sides of the film of the liquid tank, and the platform isconfigured to move toward and away from the film.

An embodiment of the present invention utilizes the fluid tunnel(s)disposed on the plate, the lifting device(s) for lifting the film, orthe motor for inclining the workpiece and the plate with each other tobalance the pressure along the two sides of the film, thus eliminatingthe low-pressure/vacuum built between the film and the plate. Anembodiment of the present invention facilitates the separation ofworkpieces from the film, avoiding workpiece damages and filmdeformation, as well as improving the speed and stability ofthree-dimensional printing.

For making the above and other purposes, features and benefits becomemore readily apparent to those ordinarily skilled in the art, thepreferred embodiments and the detailed descriptions with accompanyingdrawings will be put forward in the following descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more readily apparent to thoseordinarily skilled in the art after reviewing the following detaileddescription and accompanying drawings, in which:

FIG. 1 is a schematic illustration of a liquid tank according to anembodiment of the present invention;

FIG. 2A is a schematic illustration of a workpiece separating from afilm of the liquid tank of FIG. 1;

FIG. 2B is a schematic illustration of a workpiece separating from afilm of a liquid tank according to another embodiment of the presentinvention;

FIGS. 3A and 3B are schematic illustrations of plates according to yetanother two embodiments of the present invention;

FIG. 4 is a schematic illustration of a liquid tank according to anotherembodiment of the present invention;

FIG. 5 is a schematic illustration of the actuation of the embodimentaccording to FIG. 4;

FIG. 6 is a schematic illustration of a three-dimensional printingapparatus according to an embodiment of the present invention;

FIG. 7 is a schematic illustration of a three-dimensional printingapparatus according to an embodiment of the present invention;

FIG. 7A is a schematic illustration of separation of the film from theplate according to the embodiment illustrated in FIG. 7;

FIG. 7B is a schematic illustration of separation of the workpiece inthe liquid tank from the film according to the embodiment illustrated inFIG. 7;

FIG. 8 is a schematic illustration of separation of the film from theplate according to an embodiment of the present invention;

FIG. 9 is a schematic illustration of a three-dimensional printingapparatus according to an embodiment of the present invention;

FIG. 9A is a schematic illustration of separation of the film from theplate according to the embodiment illustrated in FIG. 9;

FIG. 9B is a schematic illustration of separation of the workpiece inthe liquid tank from the film according to the embodiment illustrated inFIG. 9; and

FIG. 10 is a schematic illustration of separation of the film from theplate according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more specifically withreference to the following embodiments. It is to be noted that thefollowing descriptions of preferred embodiments of this invention arepresented herein for purpose of illustration and description only. It isnot intended to be exhaustive or to be limited to the precise formdisclosed.

Referring now to FIG. 1. A liquid tank 100 of the present embodiment isapplicable to a three-dimensional printing apparatus, and is configuredto accommodate a photosensitive liquid 10. The liquid tank 100 includesa film (a release layer) 110 and a plate 130. The film 110 has a workingarea (a workpiece curing area) R, onto which a curing light beamprovided by the three-dimensional printing apparatus irradiates. Theplate 130 supports the film 110, and has a first area R1 correspondingto the working area R and a second area R2 adjacent to the first areaR1. The second area R2 has at least one fluid tunnel (fluid passage) 133extending from a surface 134 of the plate 130 contacting the film 110 toanother surface of the plate 130; for example, a surface 135 opposite tothe surface 134. In another embodiment of the present invention, thefluid tunnel 133 is located in the first area R1.

The liquid tank 100 may include a plurality of side walls 120surrounding the film 110. An accommodating space 121 is formed betweenthe side walls 120 and the film 110 for accommodating the photosensitiveliquid 10. Additionally, the film 110 is a flexible film made of softmaterials, and is light transmissive. The film 110 may also be weaklyadhesive to surfaces; more specifically, the film 110 may, but is notlimited to, be made of silicone or polytetrafluoroethylene.

The second area R2 of the plate 130 surrounds the first area R1. Inanother embodiment, the second area R2 may be disposed on a side of thefirst area R1. Moreover, the second area R2 in this embodiment includesone fluid tunnel 133; in other embodiments, the second area R2 mayinclude a plurality of fluid tunnels 133. Furthermore, the plate 130 maybe made of glass, plastics, acrylates, or other materials capable ofproviding sufficient support. The plate 130 may also be lighttransmissive. The fluid tunnel 133 linearly extends from the surface 134of the plate 130 to the surface 135 opposite to the surface 134.

Referring now to FIG. 2A. The photosensitive liquid 10 is cured in theworking area R to form a workpiece 20 adhered (attached) to a platform(curing platform) 300 of the three-dimensional printing apparatus.

Thereafter, uplift of the workpiece 20 by the platform 300 allows fluidF to flow through the fluid tunnel 133 and enter the space between thefilm 110 and the surface 134 of the plate 130, therefore eliminatinglow-pressure/vacuum (low-pressure vacuum) built up between the film 110and the plate 130 and balancing the pressure along the two sides of thefilm 110. The workpiece 20 may be easily separated from the film 110 byapplying an uplift force that is greater than only the adhesive forcebetween the workpiece 20 and the film 110, allowing the photosensitiveliquid 10 to fill between the workpiece 20 and the film 110 so as toinitiate printing of the following layer. Consequently, the liquid tank100 of the present embodiment greatly reduces the uplift force requiredto separate the workpiece 20 from the film 110, and thus damage of theworkpiece 20 or deformation of the film 110 can be avoided.

Referring now to FIG. 2B. In another embodiment, the liquid tank 100 afurther includes a fluid driver 140, e.g. a pumper, connecting to thefluid tunnel 133 for driving the fluid F to flow through the fluidtunnel 133. More specifically, after formation of each layer of theworkpiece 20, fluid driver 140 would drive the fluid F to flow throughthe fluid tunnel 133 and enter the space between the film 110 and thesurface 134 of the plate 130; in this way, low-pressure/vacuum built upbetween the film 110 and the plate 130 is eliminated and pressure alongthe two sides of the film 110 is balanced, therefore facilitating theseparation of workpiece 20 from the film 110. Thereafter, the fluiddriver 140 would clear the fluid F out from the space between the film110 and the surface 134 of the plate 130 via the fluid tunnel 133,allowing the film 110 to sit smoothly over the plate 130 and ensuringprecision of the following printings by preventing residual fluid F toremain between the film 110 and the surface 134 of the plate 130.

The fluid F may be gas, such as air, nitrogen, or other types of gascommonly used in manufacturing and processing. The fluid F may also beliquid, such as water.

In other embodiments as illustrated in FIGS. 3A and 3B, a fluid tunnel133 a may non-linearly or meanderingly extend from the surface 134 ofthe plate 130 a to the surface 135 opposite to the surface 134. A fluidtunnel 133 b may also extend from the surface 134 of the plate 130b tothe surface 136 adjacent to the surface 134.

Referring now to FIG. 4. Another embodiment of the present inventionprovides a liquid tank 100 b applicable to a three-dimensional printingapparatus. The liquid tank 100 b is configured for accommodating aphotosensitive liquid 10, and includes a film 110, a plate 130 c, and atleast one lifting device 150. The liquid tank 100 b may further includea plurality of side walls 120. The film 110 and the side walls 120 ofthe present embodiment are structurally similar to those of theaforementioned embodiments; redundant details thereof are thus notrepeatedly provided herein. The liquid tank 100 b of the presentembodiment is different from the liquid tank 100 of the aforementionedembodiments mainly in that the plate 130 c supporting the surface 112 ofthe film 110 does not include a fluid tunnel and that the at least onelifting device 150 is disposed adjacent to the plate 130 c and propsagainst the surface 112. The at least one lifting device 150 isconfigured for lifting the film 110 so as to separate at least a portionof the film 110 from the plate 130 c.

Taking the embodiment illustrated in FIG. 4 for example, two liftingdevices 150 may be symmetrically disposed on two sides of the plate 130c. In other embodiments, one lifting device 150 may be disposed on oneside of the plate 130 c (not shown in figure), or a plurality of liftingdevices 150 may surround or encircling around the plate 130 c (not shownin figure); the present invention is not limited thereto however.

Referring now to FIG. 5. After the photosensitive liquid 10 is cured toform a workpiece 20, the lifting device 150 shifts upward and lifts thefilm 110 by propping against the surface 112, therefore separating thefilm 110 from the plate 130 c and allowing the fluid F to enter thespace between plate 130 c and surface 112 of the film 110. Consequently,low-pressure/vacuum built up between the film 110 and the plate 130 c iseliminated and pressure along the two sides of the film 110 is balanced,thus effectively reducing the uplift force required to separate theworkpiece 20 and the film 110 and preventing damage of the workpiece 20or deformation of the film 110. Furthermore, the lifting device 150 maybe adopted in any of the aforementioned embodiments in which at leastone liquid passage is present in the plate.

Referring now to FIG. 6. An embodiment of the present invention providesa three-dimensional printing apparatus 400, which includes a lightsource device 200, a platform 300, and any one of the liquid tanks ofthe aforementioned embodiments. It is to be understood that the liquidtank 100 in FIG. 6 is identical to the liquid tank 100 illustrated inFIG. 1. The liquid tank 100 is configured to accommodate thephotosensitive liquid 10; the light source device 200 is disposed belowthe liquid tank 100 for providing a curing light beam I that passesthrough the plate 130 and irradiates the working area R. The lightsource device 200 may be, but is not limited to, a digital lightprocessing (DLP) projection device or other types of projection device(e.g. LCOS, LCD). The platform 300 and the plate 130 are disposed on twoopposite sides of the film 110 of the liquid tank 100. The platform 300is configured to move toward and away from the film 110.

Upon irradiation of the photosensitive liquid 10, the workpiece 20 isformed in the working area R and adhered to the platform 300. Theplatform 300 moves away from the film 110 so that the workpiece 20 islifted upward and separates from the film 110. During the separation,presence of the fluid tunnel 133 would eliminate the low-pressure/vacuumbuilt between the film 110 and the plate 130 and balance the pressurealong the two sides of the film 110. Consequently, the workpiece 20 maybe easily separated from the film 110 by applying an uplift force thatis greater than only the adhesive force between the workpiece 20 and thefilm 110, allowing the photosensitive liquid 10 to fill between theworkpiece 20 and the film 110 so as to initiate the following printings.

Referring now to FIG. 7. An embodiment of the present provides athree-dimensional printing apparatus 400a, which includes a liquid tank100 and a motor 160. The liquid tank 100 is configured to accommodatethe photosensitive liquid 10, and includes a film 110 and a plate 130.The liquid tank 100 may further include a plurality of side walls 120.The film 110, the side walls 120, and the plate 130 of the presentembodiment are structurally similar to those of the aforementionedembodiments as illustrated in FIG. 1 to FIG. 3B; redundant detailsthereof are thus not repeatedly provided herein. The three-dimensionalprinting apparatus 400a of the present embodiment is different from thethree-dimensional printing apparatus 400 of the aforementionedembodiment mainly in that it uses the motor 160, which is disposed belowthe film 110, the side walls 120, and the plate 130, and the fluidtunnel 133 of the plate 130, which supports the film 110, together toachieve the purpose of easier separation of the workpiece 20 from thefilm 110.

In this embodiment, the motor 160 is disposed on one of the side walls120 cooperating with a pivot 162 on another side wall 120; the presentinvention is not limited thereto however. In other embodiments of thepresent invention, the motor 160 and the pivot 162 may be disposed onone of two opposite ends of the plate 130 of the liquid tank 100; aposition of the motor 160 is not limited herein however. The motor 160and the pivot 162 can be disposed on different sides of the side walls120 in different cases.

FIG. 7A illustrates separation of the film 110 from the plate 130, andFIG. 7B illustrates separation of the workpiece 20 in the liquid tank100 from the film 110.

Referring now to FIG. 7A. A photosensitive liquid 10 is cured in aworking area R to form the workpiece 20 adhered to a platform 300 of thethree-dimensional printing apparatus. Thereafter, dragging-down tractionprovided by the motor 160 on one of the side walls 120 makes anotherside wall 120 rotates along the pivot 162. Rotation of the side walls120 also drives rotation of the plate 130 along the pivot 162. At leasta portion of the plate 130 moves away from the film 110 to form aninterval G1 between the portion of the plate 130 and the workpiece 20and make the surface 134 of the plate 130 slant/inclined to an adhesivesurface 201, which is the surface of the workpiece 20 adheres to thefilm 110. An angle 01 is measured between the surface 134 of the plate130 and the adhesive surface 201 of the workpiece 20. Thus, it allowsfluid F to flow through the fluid tunnel 133 and also peripheral regionsof the plate 130 to enter the space between the surface 134 of the plate130 and the film 110. Consequently, low-pressure/vacuum built up betweenthe film 110 and the plate 130 is eliminated and pressure along the twosides of the film 110 is balanced.

Referring now to FIG. 7B. A shearing component force is formed by thefilm 110. When the workpiece 20 is uplifted by the platform 300, theshearing component force makes the film 110 gradually separating fromthe workpiece 20 along the adhesive surface 201, allowing thephotosensitive liquid 10 to fill the space between the workpiece 20 andthe film 110 so as to initiate printing of the following layer. It isnoted that, in the three-dimensional printing apparatus 400 a of thepresent embodiment, separation of the workpiece 20 from the film 110 canbe achieved by the motor 160 and presence of the fluid tunnel 133 of theplate 130 together. Consequently, the liquid tank 100 of the presentembodiment greatly reduces the uplift force required to separate theworkpiece 20 from the film 110. And thus, not just damages of theworkpiece 20 or deformation of the film 110 can be avoided, but alsoeffectively reduce time consuming for forming the workpiece 20 by easierand faster separation of the workpiece 20 from the film 110. Productyields of large workpeices can be therefore highly improved.

In the present embodiment, the angle θ1 between the surface 134 of plate130 and the adhesive surface 201 of the workpiece 20 is in a range of0-5 degrees; the present invention is not limited thereto however. Inanother embodiment of the present invention, the angle θ1 is in a rangeof 0-10 degrees; and in another embodiment of the present invention, theangle θ1 is in a range of 0-30 degrees.

In the present embodiment, the interval G1 between at least a portion ofthe plate 130 and the workpiece 20 is in a range of 0-15 mm; the presentinvention is not limited thereto however. In another embodiment of thepresent invention, the interval G1 between at least a portion of theplate 130 and the workpiece 20 is in a range of 0-20 mm; and in anotherembodiment of the present invention, the interval G1 between at least aportion of the plate 130 and the workpiece 20 is in a range of 0-30 mm.

The motor 160 of the present embodiment is a stepper motor; the presentinvention is not limited thereto however. In other embodiments of thepresent invention, the motor 160 may be other types of motors, such as avoice coil motor, or other devices/elements, such as spring orpiezoelectric materials, to accomplish the same function; however, thepresent invention is not limited thereto. Any devices or elements canmake the surface 134 of the plate 130 inclined with respect to theadhesive surface 201 of the workpiece 20 can be applied.

Referring now to FIG. 8, which illustrates separation of a film 110 froma plate 130 according to another embodiment of the present invention. Aphotosensitive liquid 10 is cured in a working area R to form aworkpiece 20 adhered to a platform 300. Thereafter, uplift of theworkpiece 20 by the platform 300 allows fluid F to flow through thefluid tunnel 133 and enter a space between the film 110 and a surface134 of the plate 130, therefore eliminating low-pressure/vacuum built upbetween the film 110 and the plate 130 and balancing the pressure alongthe two sides of the film 110.

After separation of the film 110 from the plate 130 by uplift of theworkpiece 20 by the platform 300, a motor 160 drags one of the sidewalls 120 down so as to make another side wall 120 rotating along apivot 162. Rotation of the side walls 120 also drives rotation of theplate 130 along the pivot 162. The surface 134 of the plate 130 isgradually inclined so as to form an angle θ1 between the surface 134 ofthe plate 130 and the adhesive surface 201 of the workpiece 20. Theworkpiece 20 thus separates from the film 110, allowing thephotosensitive liquid 10 to fill the space between the workpiece 20 andthe film 110 so as to initiate printing of the following layer. Detailsof the aforementioned movements of dragging down and separation of theworkpiece 20 from the film 110 are similar to illustration in FIG. 7Aand FIG. 7B.

Referring now to FIG. 9. An embodiment of the present invention providesa three-dimensional printing apparatus 400 b, which includes a liquidtank 100 and a motor 160 b. The liquid tank 100 is configured toaccommodate the photosensitive liquid 10, and includes a film 110 and aplate 130. The liquid tank 100 may further include a plurality of sidewalls 120. The film 110, the side walls 120, and the plate 130 of thepresent embodiment are structurally similar to those of theaforementioned embodiments as illustrated in FIG. 1 to FIG. 3B, andredundant details thereof are thus omitted for purpose of brevity. Thethree-dimensional printing apparatus 400 b of the present embodiment isdifferent from the three-dimensional printing apparatus 400 a of theaforementioned embodiment mainly in that the motor 160 b is disposed onthe platform 300. In the present embodiment, the plate 130 is alsoconfigured to support the film 110 and includes at least one fluidtunnel 133. Moreover, the present embodiment, similar to aforementionedembodiment, uses the motor 160 b and the fluid tunnel 133 of the plate130 together to achieve the purpose of easier separation of theworkpiece 20 from the film 110.

In the present embodiment, the motor 160 b is disposed on one end of theplatform 300, and a pivot 164 is disposed on an opposite end of theplatform 300. However, it is for illustration only but not intended tolimit the present invention.

FIG. 9A illustrates separation of the film 110 from the plate 130, andFIG. 9B illustrates separation of the workpiece 20 from the film 110 inthe liquid tank 100.

Referring now to FIG. 9A, a photosensitive liquid 10 is cured in aworking area R to form the workpiece 20 adhered to a platform 300.Thereafter, pull-up traction provided by the motor 160 b on the end ofthe platform 300 makes the opposite end of the platform 300 rotatesalong the pivot 164 so as to drive rotation of the entire platform 300.At least a portion of the platform 300 shifts away from the film 110 toform an interval G2 between the portion of the platform 300 and theworkpiece 20 and make a surface 134 of the plate 130 inclined withrespect to an adhesive surface 201 of the workpiece 20. An angle θ2 ismeasured between the surface 134 of the plate 130 and the adhesivesurface 201 of the workpiece 20. Thus, it allows fluid F to flow throughthe fluid tunnel 133 and also peripheral regions of the plate 130 toenter the space between the surface 134 of the plate 130 and the film110. Consequently, low-pressure/vacuum built up between the film 110 andthe plate 130 is eliminated and pressure along the two sides of the film110 is balanced.

Referring now to FIG. 9B. A shearing component force is formed by thefilm 110. When the workpiece 20 is uplifted by the platform 300, theshearing component force makes the film 110 gradually separating fromthe workpiece 20 along the adhesive surface 201, allowing thephotosensitive liquid 10 to fill between the workpiece 20 and the film110 so as to initiate printing of the following layer. It is noted that,in the three-dimensional printing apparatus 400 b of the presentembodiment, separation of the workpiece 20 from the film 110 can beachieved by the motor 160 and presence of the fluid tunnel 133 of theplate 130 together. Consequently, the liquid tank 100 of the presentembodiment greatly reduces the uplift force required to separate theworkpiece 20 from the film 110. And thus, not just damage of theworkpiece 20 or deformation of the film 110 can be avoided, but alsotime consumption for forming the workpiece 20 can be effectively reducedby easier and faster separation of the workpiece 20 from the film 110.Product yields of large workpeices can be therefore highly improved.

In the present embodiment, the angle θ2 between the surface 134 of plate130 and the adhesive surface 201 of the workpiece 20 is in a range of0-5 degrees; the present invention is not limited thereto however. Inanother embodiment of the present invention, the angle θ2 is in a rangeof 0-10 degrees; and in another embodiment of the present invention, theangle θ2 is in a range of 0-30 degrees.

In the present embodiment, the interval G2 between at least a portion ofthe plate 130 and the workpiece 20 is in a range of 0-15 mm; the presentinvention is not limited thereto however. In another embodiment of thepresent invention, the interval G2 is in a range of 0-20 mm; and inanother embodiment of the present invention, the interval G2 is in arange of 0-30 mm.

The motor 160 b of the present embodiment is a stepper motor; thepresent invention is not limited thereto however. In other embodimentsof the present invention, the motor 160 b may be other types of motors,such as a voice coil motor, or other devices/elements, such as spring orpiezoelectric materials, to accomplish the same function; however, thepresent invention is not limited thereto. Any devices or elements canmake the surface 134 of the plate 130 inclined with respect to theadhesive surface 201 of the workpiece 20 can be applied.

Referring now to FIG. 10, which illustrates separation of a film 110from a plate 130 according to another embodiment of the presentinvention. A photosensitive liquid 10 is cured in a working area R toform a workpiece 20 adhered to a platform 300. Thereafter, uplift of theworkpiece 20 by the platform 300 allows fluid F to flow through thefluid tunnel 133 and enter a space between the film 110 and a surface134 of the plate 130, therefore eliminating low-pressure/vacuum built upbetween the film 110 and the plate 130 and balancing the pressure alongthe two sides of the film 110.

After separation of the film 110 from the plate 130 by uplift of theworkpiece 20 by the platform 300, a motor 160 pulls one end of theplatform 300 upon so as to make another end of the platform 300 rotatingalong a pivot 164 so as to drive rotation of the entire platform 300. Anadhesive surface 201 of the workpiece 20 adhered on the platform 300 isgradually inclined so as to form an angle 02 between the surface 134 ofthe plate 130 and the adhesive surface 201 of the workpiece 20. Theworkpiece 20 thus separates from the film 110, allowing thephotosensitive liquid 10 to fill the space between the workpiece 20 andthe film 110 so as to initiate printing of the following layer. Detailsof the aforementioned movements of pulling up and separation of theworkpiece 20 from the film 110 are similar to illustration in FIG. 9Aand FIG. 9B.

It is important to note that the three-dimensional printing apparatus400 a as illustrated in FIG. 7 to FIG. 8 and the three-dimensionalprinting apparatus 400 b as illustrated in FIG. 9 to FIG. 10 are able tobe adopted in the framework of the three-dimensional printing apparatus400 as illustrated in FIG. 6.

An embodiment of the present invention provides a three-dimensionalprinting method for eliminating a low-pressure area built between thefilm and the plate for supporting the film during printing. The methodincludes gradually directing a fluid to flow from a portion of thelow-pressure area to fill the entire low-pressure area. Morespecifically, the fluid tunnel 133 as illustrated in FIG. 2A may beadopted to direct the fluid F to flow from the portion of thelow-pressure area connecting to the fluid tunnel 133 to gradually fillthe entire low-pressure area. Additionally or alternatively, at leastone lifting device 150 may be disposed adjacent to the plate 130 c tolift the film 110 by propping against the surface 112 of the film 110,so as to direct the fluid F to flow from the edge of thelow-pressure/vacuum area to gradually fill the entire low-pressure area.Moreover, the motor 160, disposed on the side wall 120 (or the plate130) as illustrated in FIG. 7, or the motor 160 b, disposed on theplatform 300 as illustrate in FIG. 9, is optionally included tofacilitate separation of the workpiece 20 from the film 110.

The aforementioned embodiments utilize the fluid tunnel(s), the liftingdevice(s), or motor(s) to eliminate the low-pressure/vacuum builtbetween the film and the plate, therefore effectively reducing theuplift force required to release workpieces and avoiding workpiecedamages and film deformation, as well as improving the speed andstability of three-dimensional printing. The present invention thus alsoprovides better product yields of large workpiece.

While the invention has been described in terms of what is presentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that the invention needs not be limited to the disclosedembodiment. On the contrary, it is intended to cover variousmodifications and similar arrangements included within the spirit andscope of the appended claims which are to be accorded with the broadestinterpretation so as to encompass all such modifications and similarstructures.

What is claimed is:
 1. A three-dimensional printing apparatus,comprising: a liquid tank, for accommodating a photosensitive liquid,the liquid tank comprising: a film, having a working area; and a plate,for supporting the film and having at least one fluid tunnel extendingfrom a first surface of the plate contacting the film to a secondsurface of the plate; and a motor, disposed on the liquid tank,providing dragging-down traction to incline the liquid tank.
 2. Thethree-dimensional printing apparatus according to claim 1, wherein theliquid tank further comprising: a plurality of side walls, surroundingthe film.
 3. The three-dimensional printing apparatus according to claim2, wherein the motor is disposed on one of the plurality of side walls.4. The three-dimensional printing apparatus according to claim 3,further comprising: a pivot, disposed on another one of the plurality ofside walls, being as a rotation center of the liquid tank when the motoris dragging-down the liquid tank.
 5. The three-dimensional printingapparatus according to claim 1, further comprising: a pivot, disposed onone end of the plate, with the motor disposed on an opposite end of theplate, being as a rotation center of the liquid tank when the motor isdragging-down the liquid tank.
 6. The three-dimensional printingapparatus according to claim 1, wherein the motor provides dragging-downtraction to incline the first surface of the plate of the liquid tankwith respect to an adhesive surface of a workpiece.
 7. Thethree-dimensional printing apparatus according to claim 1, wherein themotor provides dragging-down traction to incline the liquid tank to forman angle between the first surface of the plate and an adhesive surfaceof a workpiece is one of the following ranges: 0-30 degrees, 0-10degrees, and 0-5 degrees.
 8. The three-dimensional printing apparatusaccording to claim 1, wherein the motor provides dragging-down tractionto incline the liquid tank to form an interval between a portion of theplate and a workpiece is in one of the following ranges: 0-30 mm, 0-20mm, and 0-15 mm.
 9. The three-dimensional printing apparatus accordingto claim 1, further comprising: a platform, disposed on a first side ofthe film of the liquid tank, with the plate disposed on a second side ofthe film of the liquid tank opposite to the first side, wherein theplatform is configured to move toward and away from the film.
 10. Thethree-dimensional printing apparatus according to claim 1, wherein theplate has a first area corresponding to the working area and a secondarea adjacent to the first area, and the fluid tunnel is in the secondarea.
 11. A three-dimensional printing apparatus, comprising: a liquidtank, for accommodating a photosensitive liquid, the liquid tankcomprising: a film, having a working area; a platform, disposed on afirst side of the film of the liquid tank, with the plate disposed on asecond side of the film of the liquid tank opposite to the first side,configuring to move toward and away from the film; and a plate, forsupporting the film and having at least one fluid tunnel extending froma first surface of the plate contacting the film to a second surface ofthe plate; and a motor, disposed on the platform, providing pull-uptraction on the platform.
 12. The three-dimensional printing apparatusaccording to claim 11, wherein the motor is disposed on a first end ofthe platform.
 13. The three-dimensional printing apparatus according toclaim 12, further comprising: a pivot, disposed on a second end oppositeto the first end of the platform, being as a rotation center of theplatform when the motor is pulling-up the platform.
 14. Thethree-dimensional printing apparatus according to claim 11, wherein themotor provides pull-up traction on the platform to incline an adhesivesurface of a workpiece with respect to the first surface of the plate.15. The three-dimensional printing apparatus according to claim 11,wherein the motor provides pull-up traction on the platform to form anangle between the first surface of the plate and an adhesive surface ofa workpiece is one of the following ranges: 0-30 degrees, 0-10 degrees,and 0-5 degrees.
 16. The three-dimensional printing apparatus accordingto claim 11, wherein the motor provides pull-up traction on the platformto form an interval between a portion of the plate and a workpiece is inone of the following ranges: 0-30 mm, 0-20 mm, and 0-15 mm.
 17. Thethree-dimensional printing apparatus according to claim 11, wherein theplate has a first area corresponding to the working area and a secondarea adjacent to the first area, and the fluid tunnel is in the secondarea.
 18. A three-dimensional printing method, for eliminating alow-pressure area built between a film and a plate for supporting thefilm of a liquid tank during printing, the method comprising: inclininga surface of the plate and an adhesive surface, adhered to the film, ofa workpiece with each other; and directing a fluid to flow from aportion of the low-pressure area to fill the entire low-pressure area.19. The three-dimensional printing method according to claim 18, whereinthe step of inclining a surface of the plate and an adhesive surface,adhered to the film, of a workpiece with each other is performed by amotor pulling up a portion of the plate.
 20. The three-dimensionalprinting method according to claim 18, wherein the step of inclining asurface of the plate and an adhesive surface, adhered to the film, of aworkpiece with each other is performed by a motor dragging down a sidewall of the liquid tank surrounding the film.